Foods products, such as meat, cheese and the like, are conventionally packaged in plastic bags using an automated bagger. The bagger feeds shingled plastic bags in a bag assembly to a workstation where a lead bag is inflated and an article is inserted into the bag. The bag is then stripped from the bag assembly and sealed. The automated bagger feeds the next bag in the shingled assembly to the workstation, the bag is inflated by an air blast and the cycle is repeated.
Packaged foods products must carry date and product source information. This information is conventionally printed on the bags in the shingled bag assembly before the bags are fed to the workstation and filled. A printer prints information on exposed sides of the bags in the shingled bag assembly. The bags overlap each other so that the surface on a bag exposed for printing extends longitudinally along the bag assembly from the end of an overlying, downstream bag to the end of the bag being printed.
The bag assemblies are manufactured by making plastic bags from plastic film and placing the bags on adhesive strips running the length of the assembly. The bags are not accurately spaced along the length of the assembly. This means that the exposed portions of the bags on the assembly which are printed are unpredictably spaced apart along the length of the assembly.
On conventional baggers feed of the bag assembly is stopped and a printer prints required information on a bag at a print area calculated to be between the end of the bag and the end of the downstream bag. Because bags are unpredictably spaced along the bag assembly, the print area may extend over the end of one bag, resulting in partial printing on one bag and partial printing on another bag. Printing of date and source information on adjacent bags is unacceptable.
Accordingly, there is a need for an improved printer assembly for a bagger using shingled bags which reliably prints product information on areas of individual shingled bags independently of longitudinal spacing of the bags along the bag assembly. Additionally, there is a need for an improved method for printing information on areas of individual shingled bags independently of the longitudinal spacing of the bags in the bag assembly.